GASIFICATION OF HIGH-ASH INDIAN COALS FOR POWER-GENERATION

Coal gasification as a route for power generation has several advantages including environmental protection and higher overall efficiency as compared to the conventional pulverised fuel system of firing. The inherent nature of Indian coals have resulted in low plant availability and wear and tear in the pulverizer and downstream sections of the thermal power generation units. Gasification of high-ash coals abundantly available in India is foreseen to be an alternate viable proposition for power generation. Fundamental and pilot plant research on gasification of these coals as conducted in moving bed, entrained bed and fluidised bed are reported and the results of tests carried out with coals of varying ash content have been briefly summarised in this paper. The tests indicate the operability of the gasification system with Indian coals. Loss in efficiency with increased oxygen consumption was observed with increased ash content of coals. Use of beneficiated coal with ash content around 25% has been envisaged to improve the overall power generation efficiency and possible beneficiation scheme of high-ash coals prior to gasification have been proposed. Further research and development activities in India on gasification of high-ash coals have also been emphasised for adopting clean coal technology programmes in India.